Process of shrink-proofing fabrics



Jan. 26, 1965 H. w. FUHR 3,166,324

PROCESS OF snamxwaoonuc FABRICS Filed July 5, 1960 United States Patent 3,166,824 PRQCESS 0F SHRlNK-PRfifiFmG FABRHCS Herbert William Fuhr, Charlotte, N .C., assignor to Cellanese Corporation of America, New York, N.Y., a corporation of Delaware Filed .luly 5, 1960, Ser. No. 40,659 {,laims. (Cl. 28 -76) The present invention relates to a novel fabric characterized by low shrinkage and other desirable properties.

Drapery fabrics formed of cellulose acetate yarns are characterized by excellent appearance but shrink appreciably on washing. Even if the yarns are blends of cellulose acetate and other fibers, synthetic or natural, the fabrics will still shrink appreciably.

It is an object of the present invention to provide novel processes for producing substantially shrinkproof fabrics composed in large measure of cellulose acetate.

C ther objects and advantages of the invention will become apparent from the following detailed description and claims.

In accordance with the present invention it has been found that woven fabrics comprising fibrous cellulose fillings, i.e. rayon or cotton, and warps of cellulose acetate can be rendered substantially shrink-proof by subjecting the fabrics to chemical treatment with finishes which render cellulose fibers shririkroof and to mechanical treatment to effect longitudinal compaction. As employed herein the term substantially shrink-prod has reference to a shrinkage of less than about 2.5% warp-wise and less than about 2% filling-wise when washed at 50 C. in an automatic washer and line dried.

It is most surprising that these treatments can produce the requisite shrink-proofness since neither 100% cellulose acetate fabrics nor fabrics having cellulose warps and cellulose acetate fillings nor fabrics having warps and fillings which are blends of cellulose acetate are rendered shrink-proof by the identical treatments.

The chemical treatment can be carried out with formaldehyde or oxymethylated, i.e. methylol, compounds, precondensates or resins such as are produced by reaction of formaldehyde with urea, melamine, ethylene, urea, or other nitrogen-containing substances, phenol, and the like. Other substances for shrink-proofing cellulose fibers, such as glyoxal or higher aldehydes, can also be employed in conventional manner. Such shrink-proofing agents are generally applied from aqueous solution or dispersion, in a concentration of about 5 to 30% and preferably about to by weight and in an amount to provide about 2 to 15% and preferably about 5 to 10% by weight of the cellulose fibers. The solution or dispersion may also contain small amounts of acidic substances to catalyze the further condenation of precondensates and/or the reaction of the shrink-proofing agents with the fibers. Softeners and/or other substances such as optical whiteners may also be present. Representative softeners include silicones, polyethylene, polyalkylene glycols, quaternary ammonium compounds, fatty amides, fatty imadazolinium compounds, and the like, applied in about 0.1 to 2% by weight of the fabric.

The chemical treatment is then completed in conventional manner as by drying at about 90 C. followed by curing at elevated temperature, e.g. 3 to 4 minutes at 150 C. Variations from this cure are permissible, the particular conditions being correlated with the chemical composition of the finish. While the chemical treatment apparently effects some measure of cross-linking, it does not significantly alter the fibrous nature of the fibers making up the warps and fillings. They retain their individuality and substantially retain their flexibility and ap pearance. The chemical treatment is apparently of only little effect on the cellulose acetate warps which have a 3,100,824 Patented Jan. 26, 1965 relatively low free hydroxyl content and are relatively hydrophobic as compared with cellulose. This minimal effect on the cellulose acetate is evidenced by the ineflicacy of such a treatment on a cellulose acetate fabric as contrasted with a 100% cellulose fabric.

The mechanical compaction can be carried out on any equipment available for this purpose such as compressive shrinking apparatus of the type that employs a rubber or felt blanket for holding the fabric against a driven roll such as is shown in United States Patent No. 1,861,424. Other suitable apparatuses are described in An Introduction to Textile Finishing, by J. T. Marsh, Chapman & Hall Ltd, 1953, ages 248 to 253, and in A Handbook of Textile Finishing, by A. J. Hall, Chemical Publishing (30., Inc., 1955, pages 188 to 193. The degree of compaction should be such that the compacted length of the fabric generally ranges from about 90 to 99% and preferably from about 94 to 97% of its length before compaction.

The invention is especially useful in rendering shrinkproof antique satin fabrics comprising closely arranged warps of continuous filament yarns of cellulose acetate having an acetyl value of about 50 to 60% and preferably about 54 to 57% calculated as combined acetic acid and less closely arranged fillings of nubby spun rayon interwoven in a manner such that one face of the fabric is predominantly warp and the other face predominantly filling. Such fabrics are especially popular for draperies since the nubby rayon face has a silk-like appearance while the lustrous acetate face gives the appearance of a lining. With these fabrics it is possible to obtain with regularity shrinkages of less than about 2% warp-wise and less than about 1.5% filling-Wise.

In accordance with another aspect of the invention, when it is desired to print such fabrics it has been found that this should preferably be carried out before the mechmical compaction. lf printing follows mechanical compaction articles made from the treated fabric may shrink somewhat in the initial laundering. When resin finishing is to precede printing, desirably the resin formulation does not include a silicone as softener or for any other purpose since its presence will result in a less deep shade than softeners which are only moderately hydrophobic.

The invention will be further described with reference to the amompanying drawing wherein:

FIG. 1 is an enlarged plan view of a portion of a preferred fabric operated uponin accordance with the invention; and I FIG. 2 is a schematic flow sheet of ance with the invention.

Referring now more particularly to the drawing, in FIG. 1 there is shown a woven fabric 11 comprising warp yarns 12 made up of continuous filament cellulose acetate yarns and filling yarns 13 made up of rayon staple fibers.

As shown in FIG. 2, the fabric 11 from a bolt 14 is passed through a bath 15 containing an aqueous solution of dimethylolethylene urea, between nip rolls 16, through an oven 17 where it is dried and cured, through Wash water 13, between nip rolls 19, through a drier 20 fed by rolls 21 to a mechanical compactor 22 and taken up at 23.

The invention will be further described in the following illustrative example.

Example 35 continuous filaments of cellulose acetate, acetyl value of 55% calculated as combined acetic acid, twisted together with 22 turns per inch into a denier yarn are woven in conventional manner as warps into a 108 x 49 construction in a 5 shaft satin weave with a 10/1 filling of nubby rayon staple fibers. By weight, the fabric comprises 40% of cellulose acetate and 60% of a process in accordrayon. The fabric is impregnated with 80% of its Weight of an aqueous solution containing 200 grams per liter of dimethylolethylene urea, grams per liter of a 35% solution of zinc nitrate and 15 grams per liter of 30% polyethylene dispersion as a softener. The fabric is dried at 90 C. for 60 sec. in a clip tenter and cured at 150 C. for 4 minutes in a curing range, washed with Water and a mildly alkaline detergent at about 60 C. and again dried. The fabric is printed on its predominantly rayon face with a- Water-in-oil resin-bonded pigment emulsion (Interchemical Aridye process) and is then dried and cured. The fabric is then sprayed to pick up about by weight of water and mechanically compacted in longitudinal direction ona Rigmel machine to decrease its length by 6%. The resulting fabric shrinks less than 0.4% over wide ranges of temperature and humidity. Different samplesof the fabric when washed at 120 F. regularly shrunk less than 1% in warp and filling and this did not increase significantly even after five washings.

It is to be understood that the foregoing detailed description is given merely by way of illustration and that many variations may be made therein without departing from the spirit of my invention.

Having described my invention what I desire to secure by Letters Patent is:

1. The process which comprises subjecting a fabric, woven of a warp yarn comprising cellulose acetate and a filling yarn comprising cellulose, to a chemical treatment for shrink-proofing cellulose and to a mechanical longitudinal compaction, whereby said fabric is rendered substantially shrink-proof, said chemical treatment comprising applying shrink-proofing agent from an aqueous medium containing a concentration of said agent of about 15 to 25% by weight.

2. The process set forth in claim 1, wherein said Warp yarn consists essentially of cellulose acetate continuous filaments and said filling yarn consists essentially of cellulose staple fiber yarn.

3. The process set forth in claim 1, wherein said fabric is printed subsequent to said chemical treatment and prior to said mechanical compaction.

4. The process set forth in claim 3, wherein said chemical treatment includes a treatment with an aqueous solution including a softener selected from the group consisting of polyethylene, polyalkylene glycols, quaternary ammonium compounds, fatty amides and fatty imidazoliniurn compounds. 7

5. The process which comprises subjecting an antique satin fabric, woven of continuous filament cellulose acetate warp yarn and a rayon staple fiber filling yarn to a chemical treatment for shrink-proofing cellulose and to a mechanical longitudinal compaction, whereby said fabric is rendered substantially shrink-proof, said chemical treatment comprising applying shrink-proofing agent from an aqueous medium containing a concentration of said agent of about 15 to 25% by weight.

6. The process set forth in claim 5, wherein said fabric predominantly comprises rayon on one face and is printed subsequent to said chemical treatment and prior to said mechanical compaction.

7. The process set forth in claim 6, wherein said chemical treatment includes a treatment with an aqueous solution including a softener selected from the group consisting of polyethylene, polyalkylene glycols, quaternary ammonium compounds, fatty amides and fatty imidazolinium compounds.

8. The process set forth in claim 5 wherein said aqueous medium includes a catalyst for said agent and said agent is selected from the group consisting of formaldehyde condensation products thereof.

9. A process which comprises treating a fabric woven of a warp yarn consisting essentially of cellulose acetate and a filling yarn consisting essentially of cellulose with an aqueous solution of a shrink-proofing agent for cellulose, curing said agent to complete a chemical shrinkproofing treatment of said filling yarn and then subjecting said fabric to a mechanical longitudinal compaction to shrink-proof said warp yarn whereby said fabric is rendered substantially shrink-proof in both warp and filling directions.

10. A process which comprises treating a fabric woven of a warp yarn consisting essentially of cellulose acetate a filling yarn consisting essentially of rayon staple fiber with an aqueous solution of a catalyst and a member selected from the group consisting of formaldehyde and condensation products thereof, curing said fabric to complete a chemical shrinlcproofing treatment of said filling yarn and then subjecting the fabric to a mechanical longitudinal compaction to shrink-proof said warp yarn whereby said fabric is rendered substantially shrink-proof in both Warp and filling directions.

References tilted by the Examiner UNITED STATES PATENTS 2,338,983 1/44 Thacltston et al 26-185 2,391,950 1/46 Croft et al. 28-76 2,585,212 2/52 Backer 139-420 2,765,513 10/56 Walton 26-186 2,828,776 4/53 Meyer 139-420 2,845,962 8/58 Bulgin 139-420 2,907,094 10/59 Murray et al. 28-76 2,911,326 11/59 Haney et al 117-1394 2,997,773 8/61 Roth et al 28-76 2,998,829 9/61 Horowitz 139-420 DONALD W. PARKER, Primary Examiner.

RUSSELL C. MADER, Examiner. 

1. A PROCESS WHICH COMPRISES SUBJECTING A FABRIC, WOVEN OF A WARP YARN COMPRISING CELLULOSE ACETATE AND A FILLING YARN COMPRISING CELLULOSE, TO A CHEMICAL TREATMENT FOR SHRINK-PROOFING CELLULOSE AND TO A MECHANICAL LONGITUDINAL COMPACTION , WHEREBY SAID FABRIC IS RENDERED SUBSTANTIALLY SHRINK-PROOF, SAID CHEMICAL TREATMENT COMPRISING APPLYING SHRINK-PROOFING AGENT FROM AN AQUEOUS MEDIUM CONTAINING A CONCENTRATION OF SAID AGENT OF ABOUT 15 TO 25% BY WEIGHT. 